Breathing apparatus



Aug. 21, 1962 1.. JONES 3,050,054

BREATHING APPARATUS Filed Aug. 1, 1957 2 Sheets-Sheet 1 INVENTOR L EON JON ES ATTORNEY Aug. 21, 1962 L. JONES 3,050,054

BREATHING APPARATUS Filed Aug. 1, 1957 2 Sheets-Sheet 2 8. m M l A E 4 M m 2 m m 8 w 8 w m H o A m o m M@ J "M I, H m A, W A w z m lrwnn MIWWHHW Mu. wllxl g: A N MQ. A m /v III A m Aw. m 8 a 2 a a m a m a mm a l a m 3 d\z c m v m 4 1 151 2 5 a 9 3 g? i United States Patent 3,050,054 BREATHING APPARATUS Leon Jones, Garden Grove, Calif., assignor to Robertshaw-Fulton Controls Company, Richmond, Va., a corporation of Delaware Filed Aug. 1, 1957, Ser. No. 675,768 9 Claims. (Cl. 128-142) This invention relates to breathing apparatus and more particularly to breathing apparatus for use in high altitude flight.

For high altitude flying where the atmospheric air is rarefied, it is desired to normally maintain a predetermined pressure of oxygen within the pilots face mask or helmet so a to provide a partial pressure of oxygen to meet physiological needs.

The most prominent disadvantage in current breathing apparatus is the effect of the oxygen pressure on the mask exhaust valve. The exhaust valve is generally positioned in the mask or helmet and comprises a balanced valve member biased into engagement with a valve seat by a spring. When the wearer of the mask exhales, the pressure within the mask will increase and move th valve member against its bias out of engagement with the seat. It is desired, of course, to maintain a minimum biasing force on the valve member whereby only a slight exhalation pressure is required to open the valve member.

Another disadvantage of current breathing apparatus is the fact that the exhaust valve tends to freeze when the moisture in the exhaled breath is transformed into ice. This results in the exhaust valve freezing in one position and becoming inoperative.

It is a principal object of this invention to compensate an exhaust valve employed in a breathing apparatus for variations in mask or helmet pressure.

Another object of the invention is to incorporate in an exhaust valve a safety device responsive to excessive mask or helmet pressure for venting the excessive fluid pressure to the atmosphere.

Another object of the invention is to arrange the components of an exhaust valve so as to effect minimum radiation of heat from the exposed surfaces thereof.

In the preferred embodiment of the invention, a casing, adapted to be mounted on a face mask or helmet, has mounted therein a valve member operative to be opened in response to an increase in pressure within the mask or helmet caused by exhalation by the user to vent exhaled air to the atmosphere. Means are provided for subjecting both sides of the valve member to the pressure of the oxygen supplied to the mask whereby the valve member is only responsive to an increase in pressure caused by exhalation. A relief valve is positioned within the casing for venting fluid pressure from the mask or helmet when the same becomes excessive during pressure breathing.

Other objects and advantages Will become apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of a breathing apparatus;

FIG. 2 is a front view of the exhaust valve shown in FIG. 1;

FIG. 3 is a rear elevation of the exhaust valve shown in FIG. 1; and

FIG. 4 is a section taken along the line IVIV of FIG. 2. I

Referring to FIG. 1, there is shown a breathing apparatus which includes a pressure reducing valve 10 connected to a suitable source of fluid or oxygen under pressure (not shown) by a conduit 12. The reducing valve 10 may be of any suitable form and serves to deliver oxygen at workable pressure to a demand-type regulator valve 14 by means of a conduit 16.

The regulator valve 14 is here shown schematically as connected to a mask or helmet 18 by means of a conduit 20. The regulator valve 14 is operative in response toinhalation by the user of the apparatus to supply fluid or oxygen to the mask or helmet 18. In addition, the regulator valve 14 is responsive to a decrease in atmospheric pressures as a result of an increase in altitude to maintain a predetermined pressure of oxygen within the conduit 20 and mask or helmet 18 toprovide pressure breathing. Regulators responsive to changes in atmospheric pressure are Well known in the art, any of which is suitable for use in the present invention. One such regulator is disclosed in United States Patent No. 2,685,288 issued to G. C. Fields et al.

A check valve 24 may be disposed within the conduit 20 to prevent flow of fluid from the mask or helmet 18 to the regulator valve 14 during exhalation by the user of the apparatus.

The mask or helmet 18 is provided With an exhaust valve indicated generally by the reference numeral 26 and which is illustrated schematically as in communication with the mask or helmet 18 by means of a conduit 28. The exhaust valve 26 is adapted to be opened by an increase in pressure within the mask or helmet 18 as a result of exhalation by the user of the apparatus to exhaust exhaled air to the atmosphere.

A relief valve 34 is illustrated as connected to the conduit 32, this valve being adapted to open if the predetermined pressure within the mask or helmet 18 should exceed a desired maximum amount to vent the excessive pressure to the atmosphere.

The regulator 14, mask or helmet 18, exhaust valve 26, and check valve 24 have been illustrated as separate units connected by conduits in FIG. 1. It will be apparent, however, to those skilled in the art that such an illustration is for the purpose of description only and that these parts may be mounted directly on the mask or helmet 18 if desired.

Referring more particularly to FIGS. 2, 3, and 4 of the drawings and to the exhaust valve 26, this valve comprises two major casing portions 38, 40 (FIG. 4) which are mounted on the mask or helmet 18. One casing portion 38 is inserted through a suitable opening in the wall of the mask from the outside thereof, and the other portion 40 is inserted over the end of the portion 38 and secured thereto by screws 4-2. A flange 44 on the end of the portion 38 is drawn tightly into engagement with the Wall of the helmet or mask 18 by the screws 42. To provide a leak-proof installation, gaskets 46 and 43 are positioned on opposite sides of the helmet wall and are engaged by the portions 38, 40, respectively.

The portion 40 is provided With an inlet port 50 for exhaled air. The exhaled air is led to the port 50 through a plastic tube 52 which has one end clamped to the casing portion 40 by means of a wedge-shaped clamp- 54 secured engagement with the knife edge 70. elongated slots 82 permit limited vertical displacement of the valve member 68 to render the same self-aligning 3 to the casing portion 40 by a screw 56. The other end of the tube 52 terminates within the mask or helmet 18.

The port 50 communicates with an interior chamber 58 defined by the casing portions 38, 40. A valve seating ring 60' of generally elliptical configuration is seated in opening 62 in the bottom Wall of the casing portion 38 and defines a valve port 64 into which exhaled air may flow from the chamber 58. A ring of sealing material 66 is fixed within the sealing ring 60' and has a knife edge 70 extending beyond the end of the ring 60.

An exhaust valve member, indicated generally by the reference numeral 68, is mounted on the casing portion 38for Cooperation with'the knife-edge 70 to control the flow of exhaled air from the valve port 64 to an exhaust port 72 in the casing portion 38. The valve member 68 comprises a thin ring 74 of generally elliptical configuration which is fixed to a complemental flange formed on the underside of a recessed supporting member 76. The support member 76 is of tapering thickness defining an upper wall disposed at arr-angle to the plane of the knife edge 70. g

The support member 76 is provided with an extended end portion 78 which has a pair of spaced ears 80 extending upwardly therefrom. Each of the ears 80 is provided with an elongated slot 82, the slots82 receiving a pin 84 fixed tothe casing portion 38.

The valve member 68 is pivotally mounted on the casing portion 38 by means of the pin 84, and is thus adapted for pivotal movement on the pin 84 into and out of In addition, the

'expansible and 'contractible diaphragm element 92 is fixed by means of an annular clamping member 94, the diaphragm-element 92 and wall 88 defining an expansible chamber '95.

A circular retainer 96 is fixed to the upper side of the valve member 68 and extends upwardly to define a cylindrical :recess for receiving the lower portion of the diaphragm 92. The lower portion of the diaphragm 92 extends into the retainer 96 and has the end thereof engaging the upper side of the valve member 68 under the bias of a spring 100 mounted in compression between the end wall of the diaphragm 92 and the underside of the supporting wall 88. The biasing force of the spring 100 serves to maintain the end portion of the diaphragm 9-2 in engagement with the valve member 68 and serves to bias the valve member 68 'into engagement with the knife edge 70.

The spring 100 encircles an inwardly projecting circular *shoulder'102 of the supporting wall 88 formed by a cylindrical recess 104 in the upper side of the supporting wall 88. The shoulder 102 serves to maintain the spring -100-in-axia1 alignment with retainer 96.

In the structure thus far described, the valve port 64 communicates with the interior of the mask or helmet I8 in order that exhaled air can flow thereto. Accordingly, the fluid pressure within the mask or helmet 18 acts on the underside of the valve member 68 tending to open the same in opposition to the biasing force of the spring 100. Exhalation on the part of the user .in-

creases the fluid pressure within the mask or helmet 18 and valve port 64 to increase the fluid pressure acting onthe underside of the valve member 68 sufliciently to overcome the biasing force of the spring 100 and eflect "openingof the valve member 68. This opening of the valve member 68 will exhaust the exhaled air to the atmosphere through port 72.

At higher altitudes Where pressure breathing is used, the fluid pressure within the mask or helmet 18 may be suflicient alone to overcome the bias of the spring prior to exhalation. The expansi'ble chamber 95 serves as a means for equalizing the fluid pressure on both sides of the valve member 68 so that the same is only responsive to exhalation pressure. To this end, fluid under pressure from the oxygen demand valve 14 is supplied to the chamber 95 by means of the conduit 32 which is secured to an inlet fitting 108 on the casing portion 38 by a clamp 110. An inlet passage 112 extends from the inlet fitting 108 and communicates with the-chamber 95 by means of a conduit 114 having one end sealed within the casing portion 40 in communication with the passage 112 and the other end thereof sealed within the casing portion 38 in communication with the chamber 95.

The relief valve 34 is positioned Within the recess 104 to vent fluid pressure from the chamber 95 if the oxygen pressure therein should exceed a predetermined maximum value. To this end, the recess 104 is enclosed by a cap member 118 which is threaded within the recess 104 and has a flange 120 tightened into engagement with the upper surface of the supporting wall 88. The upper end wall of the cap 118 is provided with a plurality of ports 12.2 which establish communication between the recess 104 and the atmosphere.

A plurality of ports 124 are provided in the bottom wall of the recess 104 to permit the flow of oxygen into the recess 104 from the chamber 95. To control the flow of oxygen into the recess 104, the valve member 126 is mounted in the recess 104 for movement into and out of engagement with the bottom wall thereof. A valve stem 128 extends from the lower side of the valve member 126 and is slidably received in a boss 130 formed in the center of the bottom wall of the recess 104. A spring 132 is mounted in compression between the valve member 126 and the cap 118 and is seated in an annular recess in the valve member 126 which maintains alignment of the spring 132.

The spring 132 exerts a biasing force on the valve member '126 tending to hold the same in engagement with the bottom wall of the recess 104. As long as the biasing force of the spring 132 is greater than the pressure force acting on the underside of the valve member 126, the valve member 126 will remainclosed. However, if the fluid pressure within the chamber '95 should increase to cause the pressure force acting on the valve member 126 to exceed the biasing force on the spring 132, the valve member 126 will be moved out of engagement with the bottom wall of the recess 104 to vent the fluid pressure in chamber 95 to the atmosphere.

In operation of the breathing apparatus, the fluid pressure within the port 50 and valve port 64 will equal the fluid pressure within chamber 95 if neither inhalation nor exhalation by the user is occurring since both port 64 and chamber 95 communicate with conduit 20. Thus, the fluid pressure in valve port 64 will exert a force on the underside of the valve member 68 which is equal to the force of the fluid pressure within the chamber 95 exerted on the upper side of the valve member 68. Accordingly, any fluid pressure in valve port 64 which is not the result of exhalation is compensated for by the fluid pressure in chamber 95, and the only effective biasing force on the valve member 68 is that exerted by the spring 100 which holds the valve member in engagement with the knife edge 70.

When the user of the apparatus exhales, the exhaled air flowing to the valve port 64 will increase the fluid pressure acting on the underside of the valve member 68 and establish a pressure differential between the valve port '64 and the chamber 95. The spring 100 is preferably selected so that this pressure differential established upon exhalation is suflicient to overcome the biasing force of the spring 100. Accordingly, when exhalation occurs, the valve member 68 will pivot clockwise on the pin 84 out of engagement with the knife edge 70 to exhaust the exhaled air to the port 72 and the atmosphere. Upon completion of exhalation, the pressure dilferential causing opening of the valve member 68 will be removed and the valve member 68 will engage the knife edge 70 under the bias of the spring 100. Alignment of the valve member 68 upon return movement thereof into engagement with the knife edge 70 is assured by the elongated slots 82 in which the pin 84 is positioned. Inhalation on the part of the user will decrease the fluid pressure within the valve port 64 and accordingly will not affect the position of the valve member 68.

If, in response to a decrease in atmospheric pressure, the demand regulator 14 should cause an increase in the fluid pressure within the mask or helmet 18, the fluid pressure in valve port 64 will increase accordingly. However, an equal increase in fluid pressure will also occur within chamber 95 to compensate for the increase of fluid pressure within port 64. Accordingly, the operation of the valve member 68 will be substantially unaffected by variations in pressure within the mask or helmet 18 caused by operation of the demand regulator 14, the valve member 68 being only responsive to the pressure differential established across the same upon exhalation by the user.

T o substantially eliminate any possible tendency of the ring 74 to stick or freeze to the knife edge 70, the valve ring 74 is formed from Teflon or similar material and provided with a lapped surface on the underside thereof for engagement with the knife edge 70. In addition, the valve seating ring 66 is formed from resilient material, such as silicon rubber. The Teflon material of the ring 74 has the physical characteristic of resisting the adhering of water to its surface at low temperature and thus forms a seat that will resist freezing at low operating temperatures normally encountered. In addition, the silicon rubber seating ring 66 offers a soft resilient seating edge to seal the port 64 when the knife edge 70 is engaged by the ring 74. This permits a minimum force to be exerted by spring 100 to effect a tight seal. Also, since the seating ring 66 is of substantial volume, it offers a substantial path for heat loss and reduces the tendency for the valve member 68 to freeze to the knife edge 7 0.

The supporting portions 76 of the valve member 68 is made of metal, such as aluminum, which being a good conductor of heat absorbs a maximum amount of heat from the exhaled air. The heat thus absorbed is conducted to the valve ring 74 and tends to prevent freezing of the same in engagement with the knife edge 7 0. The parts of the exhaust valve 26 adjacent to the valve member 68 are formed from a material of low thermal conductivity to reduce the heat transfer from the valve member 68 to the atmosphere.

While only one embodiment of the invention has been herein shown and described, it will be apparent to those skilled in the art that many changes may be made in the construction and ararngement of parts without departing from the scope of the invention as defined in the appended claims.

I claim:

1. In an exhaust valve for exhausting exhaled air from a face mask or the like of a breathing apparatus having a regulator for supplying breathing tfluid under pressure to the mask and for varying the pressure of the breathing fluid within the mask with variations in atmospheric pressure, the combination comprising a casing adapted to be supported on the mask with an inlet port in communication with the interior of the mask and an outlet port for exhausting air to the atmosphere, a valve seat intersecting said inlet and outlet ports, a valve member biased into engagement with said seat and being pivotally mounted at one end thereof for pivotal movement out of engagement with said seat against said bias in response to an increase in said fluid pressure within said inlet port acting on one side of said valve member and caused by exhalation by the user of the apparatus, and means defining an expansible chamber operatively interconnected to and exerting a force on the other side of said valve member and adapted to be connected in communication with the regulator for compensating said valve member for variations in the pressure of the breathing fluid within the mask acting on said one side of said valve member.

2. In an exhaust valve as claimed in claim 1 wherein said expansible chamber comprises a wall of said casing having an expansible diaphragm sealed thereto, said diaphragm having end wall engaging said other side of said valve member for exerting a force on said other side in response to an increase in pressure within said chamber.

3. In an exhaust valve as claimed in claim 2 wherein said biasing means comprises a spring positioned in said chamber and mounted in compression between said wall of said casing and said end wall of said diaphragm.

4. In an exhaust valve for exhausting exhaled air from a face mask or the like of a breathing apparatus having a regulator for supplying breathing fluid under pressure to the mask and for varying the pressure of the breathing fluid within the mask with variations in atmospheric pressure, the combination comprising a casing adapted to be supported on the mask with an inlet port in communication with the interior of the mask and an outlet port for exhausting air to the atmosphere, a valve seat intersecting said inlet and outlet ports, a valve member engaging said seat and pivotally mounted at one end thereof for pivotal movement out of engagement with said seat in response to an increase in fluid pressure within said inlet port acting on one side of said valve member and caused by exhalation by the user of the apparatus, means for biasing said valve member into engagement with said seat, and means defining an expansible chamber operatively interconnected to and exerting a force on the other side of said valve member in communication with the regulator for compensating said valve member for variations in the pressure of the breathing fluid within the mask acting on said one side of said valve member.

5. In an exhaust valve as claimed in claim 4 wherein said valve member is pivotally mounted by means of a pair of spaced ears on said one end of said valve member, said ears having elongated slots therein for receiving a pin fixed on said casing.

6. An exhaust valve as claimed in claim 5 wherein said expansible chamber comprises a wall of said casing having an expansible diaphragm sealed thereto, said diaphragm having an end wall engaging said other side of said valve member for exerting a force on said other side of said valve member in opposition to the pressure force acting on said one side of said valve member.

7. In an exhaust valve as claimed in claim 6 wherein said biasing means comprises a spring positioned in said expansible chamber and mounted in compression between said wall of said casing and said end wall of said diaphragm.

8. In an exhaust valve for exhausting exhaled air from a face mask or the like of a breathing apparatus having a regulator for supplying breathing fluid under pressure to the mask and means for varying the pressure of the breathing fluid within the mask with variations in atmospheric pressure, the combination comprising a casing adapted to be supported on the mask and having an inlet port in communciation with the interior of the mask and an outlet port for exhausting air to the atmosphere, a valve seat intersecting said inlet and outlet ports, a valve member biased into engagement with said seat and movable out of engagement with said seat against said bias in response to an increase in fluid pressure within said inlet port acting on one side of said valve member and caused by exhalation by the user of the apparatus, means defining an expansible chamber on the other side of said valve member including a wall of said casing overlying said valve member and an expansible diaphragm sealed to said wall and having an end wall engaging said other side of said valve member, said expansible chamber being adapted for connection in communication with said regulator for exerting a pressure force on said other side of said valve member to compensate for variations in pressure in said inlet port caused bysaid regulat0r,.and valve means associated with said wall of said casing forventing fluid pressure from said expansible chamber in response to the occurrence of a predetermined excessive pressure condition caused by the regulator.

9. in an exhaust valve as claimed in claim 8 wherein said valve means comprsies a valve port in said casing wall in communication with the atmosphere and said expansible chamber, and a valve member biased into engagement withsaid casing wall to control communication between 8 said expansible chamber and the atmosphere through said port, said valve member being moved out of engagement with said wall against said bias when the pressure within said chamber exceeds the biasing force of said valve 5 member.

References Cited in the file of this patent UNITED STATES PATENTS 2,685,288 Fields et al Aug. 3, 1954 2,764,151 Cupp Sept. 25, 1956 2,810,386 Reed Oct. 22, 1957 

